A group of entomologists has found more than 40 new species of beetles on the steep slopes of the Tahitian mountains.

The team hiked into areas only accessible from helicopter drop-off points, and never before visited by scientists.

Tahiti is home to some of the most diverse insect populations in the world.

Professor James Liebherr from Cornell University in New York led the expedition and says it's uncommon to have so many different kinds of beetles in one place.

“The significance in my mind is that the amount of diversity in Tahiti is all restricted to Tahiti.

"They are all endemic species.

"You go to any particular ridges that make up the volcano Tahiti Nui, and there’s been extensive erosion and many of these ridges are quite isolated, and you go ridge to ridge, even then you find different species," he told Pacific Beat.

“The older volcano on Tahiti is only 1.4 million years old and we’ve discovered over 100 species there, so these things are clicking along at a very rapid rate."

Professor Liebherr believes many of the beetles can be traced back to one found in Australia.

“My hypothesis is that it's a very, very common species found across Australia.

"It has wings, it flies, you could be in Sydney or in Perth...it doesn’t matter, it’s everywhere.”

"But when you get back to these island systems the flight wings have been lost, evolutionarily and at that point the ranges become much smaller."

"They become homebodies, they can’t fly, they simply stay where they are and the populations diverge.”

The group didn't discover any hybrid species, because they tend to stay in one place and breed with their neighbours.

"You’ll have small populations, perhaps on a ridge constrained by a forest-type or levels of precipitation or particular tree species and they don’t occur anywhere else, and as the slopes fall away in between they’re left high and dry,” Professor Liebherr says.

"We also found on this trip that there were other things that specialise on wet rock faces, so they're living between the layers of volcanic rock where springs are coming out of the ground.

"Other ones are specific to particular types of vegetation and seem not to be found on other things. and so they're very, very specific ecologically."

Professor Leibherr says it’s highly likely there are many more species to be discovered in Tahiti.

“There are four major massifs in the south end of Tahiti Nui that no entomologist has ever been on, so the work certainly hasn’t been done.